P0304 & P0316
#1
P0304 & P0316
Hey everyone. I have a 2006 Ford Ranger XLT 3.0L and it has been idling hard and when I try to drive it after accelerating the check engine light begins flashing and the truck shakes. I did a scan and received codes P0304 and P0316. I just changed the spark plugs and spark plug wires and it seemed to be a lot less shaky, the check engine light went off, but when I revved it up it sounded like it was misfiring again and I put the code reader in and it shot back the P0304 and P0316 codes again.
Anyone know what it could possibly be or what I should do?
The truck only has 87,000 miles on it and has been kept up with oil changes and stuff like that.
Anyone know what it could possibly be or what I should do?
The truck only has 87,000 miles on it and has been kept up with oil changes and stuff like that.
#2
#3
RF Veteran
iTrader: (1)
This is the Ford TSB about '04-'06 3.0l engines, although it seems to be an issue back to the '01 3.0ls
Just to add there was also a TSB about the 3.0l Coil Packs on these years as well, can't find it, it had serial number range for the coils that were causing the problem of random misfires.
**************************
TSB 05-26-3
FORD: 2004-2006 Ranger
ISSUE
Some 2004-2006 Rangers 3.0L-2V "Vulcan"vehicles may exhibit:
- Malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P0300-P0306 and P0316
- Rough running at various RPM
- Rough idle
- Misfire
ACTION
This may be due to an engine exhaust valve seat recession causing a loss of compression. Refer to the following Service Procedure to diagnose exhaust valve seat recession.
SERVICE PROCEDURE
1. Perform a power balance rest to clarify if a cylinder is misfiring. Identify and keep record of any cylinder that has a concern.
2. Perform a manual compression test with the spark plugs removed to locate any cylinder that may have low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.
3. If no low compression is found per shop manual instructions, proceed with normal misfire diagnostics per the Powertrain Controls/Emissions Diagnosis (PC/ED) Manual for the appropriate model year.
4. If low compression is found and it is a cylinder that had a misfire on power balance, perform a leakdown test to determine the source of leakage that may be causing the low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.
5. If low compression is found in a cylinder that did not have a misfire detected then proceed with normal base engine diagnostics per the Workshop Manual, Engine System, General Information, 303-00.6.
If the exhaust valve is identified as the source, replace both cylinder heads with the newly released service cylinder heads. Refer to the appropriate Workshop Manual, Section 301-01A.
PART NUMBER / PART NAME
6U7Z-6049-A / Cylinder Head Assembly
Just to add there was also a TSB about the 3.0l Coil Packs on these years as well, can't find it, it had serial number range for the coils that were causing the problem of random misfires.
**************************
TSB 05-26-3
FORD: 2004-2006 Ranger
ISSUE
Some 2004-2006 Rangers 3.0L-2V "Vulcan"vehicles may exhibit:
- Malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P0300-P0306 and P0316
- Rough running at various RPM
- Rough idle
- Misfire
ACTION
This may be due to an engine exhaust valve seat recession causing a loss of compression. Refer to the following Service Procedure to diagnose exhaust valve seat recession.
SERVICE PROCEDURE
1. Perform a power balance rest to clarify if a cylinder is misfiring. Identify and keep record of any cylinder that has a concern.
2. Perform a manual compression test with the spark plugs removed to locate any cylinder that may have low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.
3. If no low compression is found per shop manual instructions, proceed with normal misfire diagnostics per the Powertrain Controls/Emissions Diagnosis (PC/ED) Manual for the appropriate model year.
4. If low compression is found and it is a cylinder that had a misfire on power balance, perform a leakdown test to determine the source of leakage that may be causing the low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.
5. If low compression is found in a cylinder that did not have a misfire detected then proceed with normal base engine diagnostics per the Workshop Manual, Engine System, General Information, 303-00.6.
If the exhaust valve is identified as the source, replace both cylinder heads with the newly released service cylinder heads. Refer to the appropriate Workshop Manual, Section 301-01A.
PART NUMBER / PART NAME
6U7Z-6049-A / Cylinder Head Assembly
#5
Ron I am pulling codes p0302 and p0316 in my 2004 ford ranger 3.0l manual 4x2 vin u
I have recently replaced both cylinder heads with (new) heads
replaced head gasket
replaced thermostat
replaced ignition coil pack all spark plugs and wires
i have 160 or better compression in all cylinders and the vehicle is getting 21.75mpg
it is idling low around 700rpm
the fuel injector in cylinder 2 sounds like it is working properly but haven't done an ohm test on it.
Is there anything else you would recommend looking into?
I have recently replaced both cylinder heads with (new) heads
replaced head gasket
replaced thermostat
replaced ignition coil pack all spark plugs and wires
i have 160 or better compression in all cylinders and the vehicle is getting 21.75mpg
it is idling low around 700rpm
the fuel injector in cylinder 2 sounds like it is working properly but haven't done an ohm test on it.
Is there anything else you would recommend looking into?
#6
RF Veteran
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Welcome to the forums
So you were getting these misfire codes BEFORE changing the heads?
And then the same codes AFTER changing the heads?
If so yes I would change or swap around injector #2 so see if that solved the problem
Warm idle of 700rpms is not that low for a manual
COLD idle should be 1,000rpms, if not then first replace the ECT Sensor, it sets Choke mode and higher idle when cold
Did the pushrods and lifters seem OK?
So you were getting these misfire codes BEFORE changing the heads?
And then the same codes AFTER changing the heads?
If so yes I would change or swap around injector #2 so see if that solved the problem
Warm idle of 700rpms is not that low for a manual
COLD idle should be 1,000rpms, if not then first replace the ECT Sensor, it sets Choke mode and higher idle when cold
Did the pushrods and lifters seem OK?
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Zman12 (03-28-2021)
#7
Thank you for the reply Ron I am new to the forums and trying to figure out how to use them properly, thank you for your patience.
I bought the truck in a non running condition and did not get any codes on the scanner before tear down.
The lifters and push rods all looked to be in great condition and the new cylinder heads came with new valves and springs.
I also check the resistance this afternoon on the injectors and was getting 13.5 across the board
I have also replaced the fuel pump already (realized the previous one wasn't working after putting the engine back together) and the fuel filter because it had been non op for over a year there was next to no gas in the tank when I opened it up and I've filled it with 91
Tp% is 17.6 at idle
short fuel trim 1 is -3.1
long fuel trim 1 is -7.8
short fuel trim 2 is 0.0
long fuel trim 2 is -4.7
I bought the truck in a non running condition and did not get any codes on the scanner before tear down.
The lifters and push rods all looked to be in great condition and the new cylinder heads came with new valves and springs.
I also check the resistance this afternoon on the injectors and was getting 13.5 across the board
I have also replaced the fuel pump already (realized the previous one wasn't working after putting the engine back together) and the fuel filter because it had been non op for over a year there was next to no gas in the tank when I opened it up and I've filled it with 91
Tp% is 17.6 at idle
short fuel trim 1 is -3.1
long fuel trim 1 is -7.8
short fuel trim 2 is 0.0
long fuel trim 2 is -4.7
#9
RF Veteran
iTrader: (1)
The data looks good
Throttle position sensor is a 5volt sensor so............
0% is 0 volts
100% is 5 volts
Closed throttle voltage should be just under 1 volt, 0.69-0.99v is spec, 1 volt would be 20% of 5 volts, so 17.6% would be spot on for idle/throttle closed, just under 1volt
And Wide Open throttle should be 4.5-4.8volts, so above 90% but NEVER 100%
Fuel trims are the OPEN TIME for fuel injectors
Computer calculates 0 STFT for each Bank/side of a V6 engine, based on RPMs, load and sensor data, say OPEN TIME is 100ms(milliseconds)
Passenger side is Bank 1
Drivers side is Bank 2
The computer then opens the injectors for 100ms, and waits for feed back from O2 sensor on that Bank
If O2 shows high Oxygen level(lean) then computer OPENS injector 2% longer, 102ms, +2% STFT
Then sees what O2 data shows now, if still too much Oxygen then +4% STFT, and +6% STFT, ect......
If O2 data showed too little Oxygen, then -2% STFT(98ms), and -4% STFT(96ms), ect.....
All this takes maybe 5-10 seconds so engine is never running Lean or Rich
STFT between -10 and +10 are fairly normal
LTFT(long term fuel trim) is used so engine systems can age gracefully, as a vehicle gets older there will be small vacuum leaks and fuel pump pressure can drop a bit, MAF gets dirty, throttle body gets dirty, ect..............i.e. a used engine, lol
LTFT is an average of STFT on each bank over time, so if the last time you drove the vehicle the LTFT was -7% then on cold start(no O2 sensors) the computer would do its calculations and then ADD LTFT, so if OPEN TIME calculated was 100ms(STFT 0), then it would be changed to 93ms, 100 - 7% = 93(new STFT 0)
LTFT allows Cold engines to run better, O2 sensor need to be heated above 650degF in order to work, which is why they are "Heated" O2 sensor to warm then up faster
So O2 data can not be used until engine coolant temp is above about 160degF, 190degF is normal operating temp
To know actual STFT you need to add STFT and LTFT together
So your Bank 1 STFT is actually -10.9% which is high(well low, lol)
Negative fuel trims can only be a few things
High Fuel pressure, 2006 should be about 55psi, there is a fuel pressure regulator in the gas tank
Leaking/sticking fuel injectors, look at spark plug tips, they will show carbon build up
Leaking EGR valve
Leaking valve guide seals, burning oil, will also show up on spark plug tips
Failing O2 sensor, but BOTH upstream O2 show Rich so unlikely
If a vehicle is used for short trips so doesn't get fully warmed up, i.e. not driven more than 15 minutes at a time, then that can cause this as well
Throttle position sensor is a 5volt sensor so............
0% is 0 volts
100% is 5 volts
Closed throttle voltage should be just under 1 volt, 0.69-0.99v is spec, 1 volt would be 20% of 5 volts, so 17.6% would be spot on for idle/throttle closed, just under 1volt
And Wide Open throttle should be 4.5-4.8volts, so above 90% but NEVER 100%
Fuel trims are the OPEN TIME for fuel injectors
Computer calculates 0 STFT for each Bank/side of a V6 engine, based on RPMs, load and sensor data, say OPEN TIME is 100ms(milliseconds)
Passenger side is Bank 1
Drivers side is Bank 2
The computer then opens the injectors for 100ms, and waits for feed back from O2 sensor on that Bank
If O2 shows high Oxygen level(lean) then computer OPENS injector 2% longer, 102ms, +2% STFT
Then sees what O2 data shows now, if still too much Oxygen then +4% STFT, and +6% STFT, ect......
If O2 data showed too little Oxygen, then -2% STFT(98ms), and -4% STFT(96ms), ect.....
All this takes maybe 5-10 seconds so engine is never running Lean or Rich
STFT between -10 and +10 are fairly normal
LTFT(long term fuel trim) is used so engine systems can age gracefully, as a vehicle gets older there will be small vacuum leaks and fuel pump pressure can drop a bit, MAF gets dirty, throttle body gets dirty, ect..............i.e. a used engine, lol
LTFT is an average of STFT on each bank over time, so if the last time you drove the vehicle the LTFT was -7% then on cold start(no O2 sensors) the computer would do its calculations and then ADD LTFT, so if OPEN TIME calculated was 100ms(STFT 0), then it would be changed to 93ms, 100 - 7% = 93(new STFT 0)
LTFT allows Cold engines to run better, O2 sensor need to be heated above 650degF in order to work, which is why they are "Heated" O2 sensor to warm then up faster
So O2 data can not be used until engine coolant temp is above about 160degF, 190degF is normal operating temp
To know actual STFT you need to add STFT and LTFT together
So your Bank 1 STFT is actually -10.9% which is high(well low, lol)
Negative fuel trims can only be a few things
High Fuel pressure, 2006 should be about 55psi, there is a fuel pressure regulator in the gas tank
Leaking/sticking fuel injectors, look at spark plug tips, they will show carbon build up
Leaking EGR valve
Leaking valve guide seals, burning oil, will also show up on spark plug tips
Failing O2 sensor, but BOTH upstream O2 show Rich so unlikely
If a vehicle is used for short trips so doesn't get fully warmed up, i.e. not driven more than 15 minutes at a time, then that can cause this as well
Last edited by RonD; 03-29-2021 at 09:29 AM.
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Zman12 (03-28-2021)
#10
I've read that the 2004 3.0l model did not have an egr valve and I can't seem to find one anywhere.
When I replaced the fuel pump it was the whole assembly including the lifter so unless it is a faulty product I don't feel that should be the problem however ko/er I was seeing roughly 65psi for the fuel pressure and between 40-45psi key on engine off (holds steady)
all the plugs are brand new so I will have to pull those to see if they have fouled at all, I have only put 75 miles on it since the rebuild.
I suppose that leaves me with the fuel injector, they all sound to be working with a stethoscope so I was hesitant to pull the plenum and fuel rail if it wasn't absolutely necessary.
I'm worried I may have a vacuum leak that I haven't been able to trace down, I replaced my IAC valve, but even with the brand new one not much changes when I unplug it while the truck is running.
I have not check the camshaft crankshaft or mass airflow sensors, but it seemed unlikely to me that any of those would cause a misfire in just one cylinder.
When I replaced the fuel pump it was the whole assembly including the lifter so unless it is a faulty product I don't feel that should be the problem however ko/er I was seeing roughly 65psi for the fuel pressure and between 40-45psi key on engine off (holds steady)
all the plugs are brand new so I will have to pull those to see if they have fouled at all, I have only put 75 miles on it since the rebuild.
I suppose that leaves me with the fuel injector, they all sound to be working with a stethoscope so I was hesitant to pull the plenum and fuel rail if it wasn't absolutely necessary.
I'm worried I may have a vacuum leak that I haven't been able to trace down, I replaced my IAC valve, but even with the brand new one not much changes when I unplug it while the truck is running.
I have not check the camshaft crankshaft or mass airflow sensors, but it seemed unlikely to me that any of those would cause a misfire in just one cylinder.
#11
RF Veteran
iTrader: (1)
2004 3.0l may or may not have an EGR Valve it is year specific also location specific, Calif required EGR Valves on pretty much all gasoline engines from around 1988
Have a look at #2 spark plug and compare it to #1 see if that tells you anything
I assume you can FEEL the misfire, so not computers "imagination"
And is it just at idle or can you feel it more under load?
Have a look at #2 spark plug and compare it to #1 see if that tells you anything
I assume you can FEEL the misfire, so not computers "imagination"
And is it just at idle or can you feel it more under load?
#12
#13
RF Veteran
iTrader: (1)
Just looked and 2004 Ranger 3.0l did NOT have an EGR Valve, even in Calif., even though parts stores sell them, lol
So you can stop looking
So it only misfires at High Vacuum, at idle?
Does it do it more or less when engine is cold or warm?
Or doesn't it matter?
Small vacuum leak on #2 intake runner maybe
Spray some soapy water on it, while its idling, and see if engine stumbles more, not a fan of spraying flammable liquids in engine bay, lol, but that's up to you
Put some Seafoam in gas tank, or similar injector cleaner
If an injector tip is dirty it will DRIP fuel instead of spray fuel at idle(low demand), which causes a bad fuel mix and misfires at idle but as demand goes up it sprays fuel
So you can stop looking
So it only misfires at High Vacuum, at idle?
Does it do it more or less when engine is cold or warm?
Or doesn't it matter?
Small vacuum leak on #2 intake runner maybe
Spray some soapy water on it, while its idling, and see if engine stumbles more, not a fan of spraying flammable liquids in engine bay, lol, but that's up to you
Put some Seafoam in gas tank, or similar injector cleaner
If an injector tip is dirty it will DRIP fuel instead of spray fuel at idle(low demand), which causes a bad fuel mix and misfires at idle but as demand goes up it sprays fuel
#14
Thank god I thought I was going crazy not being able to find it! lol
It is most noticeable to me at high vacuum/idle I have trouble feeling it much when I am accelerating or cruising
I will have to double check but I believe it is happening more when warm.
ran 8 oz. of seafoam through with the last half tank (had to fill it with gas cans the first time)
I will check into the intake runner and see if it is leaking anywhere next.
Also planned on testing the resistance in the new spark plug wire at the affected cylinder to make sure it wasn't a dud.
Beyond the resistance test and stethoscope test I would need to pull the injector to do any more testing correct?
It is most noticeable to me at high vacuum/idle I have trouble feeling it much when I am accelerating or cruising
I will have to double check but I believe it is happening more when warm.
ran 8 oz. of seafoam through with the last half tank (had to fill it with gas cans the first time)
I will check into the intake runner and see if it is leaking anywhere next.
Also planned on testing the resistance in the new spark plug wire at the affected cylinder to make sure it wasn't a dud.
Beyond the resistance test and stethoscope test I would need to pull the injector to do any more testing correct?
#15
RF Veteran
iTrader: (1)
Yes, if compression in #2 matches others and spark tests as OK, then injector would be the next stop
Ford uses Waste Spark, which means 2 spark plugs share 1 coil in the coil pack
Coil wiring looks like this
]1 5]
[2 6]
[3 4]
So 1/5, 2/6, 3/4 spark at the same time, only one cylinder will be on power stroke so one spark is "wasted", hence the name
I mention this because you can swap 2 and 6 spark plug wires around at the coil pack
If misfire moves to #6 then that coil in the coil pack has a problem
If you have or can lay your hands on an old timing light you can also test the spark rhythm at #2 spark plug
Ford uses Waste Spark, which means 2 spark plugs share 1 coil in the coil pack
Coil wiring looks like this
]1 5]
[2 6]
[3 4]
So 1/5, 2/6, 3/4 spark at the same time, only one cylinder will be on power stroke so one spark is "wasted", hence the name
I mention this because you can swap 2 and 6 spark plug wires around at the coil pack
If misfire moves to #6 then that coil in the coil pack has a problem
If you have or can lay your hands on an old timing light you can also test the spark rhythm at #2 spark plug
#16
I cleared the CEL this morning and put 50 miles on it after changing the IAC valve last night and I have yet to receive a new cel and feels much smoother at idle as well.
I will update if the problem reoccurs the plug wire had good resistance and the spark plug in 2 looked good (also identical to 1 and 3 I pulled those for reference)
I appreciate all the knowledge and time you have shared with me it has been very insightful!
I will update if the problem reoccurs the plug wire had good resistance and the spark plug in 2 looked good (also identical to 1 and 3 I pulled those for reference)
I appreciate all the knowledge and time you have shared with me it has been very insightful!
#17
RF Veteran
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#18
CEL came back around 80 miles it does seem to be running smoother still though.
Looking like I will need to look into that injector further, if that doesn't do the trick I may take it to a shop for a smoke test ( with my luck it will be something stupid like a hairline crack in the plastic plenum) lol
Looking like I will need to look into that injector further, if that doesn't do the trick I may take it to a shop for a smoke test ( with my luck it will be something stupid like a hairline crack in the plastic plenum) lol
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